Question

5. (05.04 MC) In an experiment, potassium chlorate decomposed according to the following chemical equation. KClO3 → KCl + O2 (Molar mass of KClO3 = 122.5 g/mol; KCl = 74.55 g/mol; O2 = 31.998 g/mol) If the mass of KCl produced was 180 grams, which of the following calculations can be used to determine the mass of potassium chlorate decomposed?

Answer 1

Answer: Given the molar masses of the reactants and products, we can calculate the number of moles of KCl produced from 180 g.

First, convert the mass of KCl to moles:

180 g / 74.55 g/mol = 2.41 moles

Next, we can use the mole ratio between KCl and KClO3 from the chemical equation to determine the number of moles of KClO3 decomposed:

2.41 moles KCl / 1 mole KClO3 = 2.41 moles KClO3

Finally, we can convert the number of moles of KClO3 to mass using its molar mass:

2.41 moles * 122.5 g/mol = 295.4875 g

Therefore, the mass of potassium chlorate decomposed was 295.4875 g.

Explanation: